7. Which of the following substances is most dense?
Answer: B
B is the most dense substance.
B, the cube weighing 6g and having a volume of 0.91cm³, has the highest density among the options provided.
A) A block of gold weighing 12g and having a volume of 4.6cm³
To determine the density of this block of gold, we calculate density as mass divided by volume: 12g / 4.6cm³ = 2.61g/cm³. While gold is a dense material, this specific sample does not have the highest density compared to option B.
B) A cube weighing 6g and having a volume of 0.91cm³
Calculating the density of this cube gives us 6g / 0.91cm³ = 6.59g/cm³, which is significantly higher than the other options. This indicates that the cube is the densest substance listed.
C) A block weighing 143g and having a volume of 24.3cm³
The density of this block is calculated as 143g / 24.3cm³ = 5.88g/cm³. Although this density is relatively high, it still does not exceed the density of option B.
D) None of the above.
This option suggests that none of the given substances are dense. However, since option B has been shown to possess the highest density, this option is incorrect.
Conclusion
Option B is the correct answer because it has the highest calculated density at 6.59g/cm³ compared to the other options. Options A and C have lower densities, and option D is incorrect as it dismisses the presence of a denser substance. Therefore, B is definitively the most dense substance among the choices provided.